1. Field of the Invention
The present invention relates to a refractory lining element for a furnace or the like, formed essentially from refractory fibers.
2. Description of the Prior Art
The linings of furnaces or similar enclosures kept at high temperature are generally constituted by refractory bricks obtained either by baking, sintering or fusion of refractory materials whose choice depends on the conditions of operation. Fireclay linings and refractory concretes are also known.
Lining elements also currently used are constituted from refractory fibers, which take advantage of the superior properties of these materials with regard to thermal insulation and lightness.
Customarily, these elements each comprise two principal walls, generally flat or with a large radius of curvature, of which one is designed to constitute the inner wall of the furnace and the other the outer wall of the lining, turned towards the metallic wall of the furnace. Small lateral walls connect the two principal walls holding them to a predetermined separation and are designed to cooperate with those of neighboring similar elements to form the lining. Two other sides are empty, so that the element appears as a tube with an elongated rectangular cross-section.
The inner gap is filled with mineral fiber after the positioning of a certain number of lining elements by stuffing from one end of one of the channels constituted by the inner gaps of the element.
It has been proposed, in U.S. Pat. No. 3,158,963, to use lining elements of non-fibrous, light refractory material, with filling of the gaps by lighter refractory material, and the technique which has been described is only the adaptation of this patent to the use of fibrous materials.
However, this adaptation has some drawbacks: the placing in position of fibers by stuffing is not always easy and does not permit complete homogeneity to be guaranteed since, with time, the fibers have a tendency to become packed in the bottom of the channel and gaps can appear towards the top, which creates a heterogeneity prejudicial to the whole.
The aforementioned U.S. Pat. No. 3,158,963 provides, it is true, for the lateral walls of the elements to be modifiable to ensure communication between the inner gaps of adjacent elements in the horizontal direction, which is of a nature to create a certain number of anchoring points for the fiber filling, but this solution does not contribute complete security and risks the creation of irregularities in the filling.
It has also been proposed, in U.S. Pat. No. 2,534,973, to constitute the filling by a stack of elements including a gap which is open in the direction of the inside of the furnace and which is closed on the other side, this gap being filled with refractory fibers, if necessary before the placing in position of the element. In this way the abovedescribed drawbacks are avoided, but the fibers are directly exposed to the atmosphere and to the substances which are in the furnace, which is of a nature to considerably reduce their longevity, even when precautions are taken to prevent them from falling inside the furnace, and it is provided for these fibers to be agglomerated together by a binder such as a cement, which reduces their insulating power.
On the other hand, the simple juxtaposition of each of the elements such as is generally practiced does not offer a sufficient guarantee of sealing in service.
It is an object of the present invention to provide an improved lining element of the aforementioned type which overcomes the abovementioned drawbacks of the prior art.
It is another object of the invention to provide an improved method of constructing a furnace lining which overcomes the abovementioned drawbacks.
Other objects and advantages will appear from the description which follows.